Fundamental criterion Ktrans for failure analysis of hydrogen-assisted cracks in notched specimens of pure Ni

Tingshu Chen, Motomichi Koyama, Shigeru Hamada, Hiroshi Noguchi

研究成果: Contribution to journalArticle査読

1 被引用数 (Scopus)


The effects of short notches on crack initiation and extension were studied under electrochemical hydrogen charging in pure nickel. In the hydrogen-charged smooth specimen, multiple cracks were initiated on grain boundaries after significant plastic deformation and were subsequently arrested by crack blunting in the interior of neighboring grains. With the assistance of sub-cracks on specimen surface, quasi-cleavage crack propagation occurred soon after, causing the final failure. The introduction of a notch did not change the crack initiation site (grain boundary). However, crack propagation exhibited significant initial notch-length dependence. A 2.5 mm notch caused quasi-cleavage crack propagation without sub-critical cracks (intergranular cracks) initiation and growth, because the notch root acted as a strongly preferential site for crack extension. However, with a smaller notch, sub-critical cracks initiation and growth were necessary to extend intergranular fracture depth and reach a critical crack length to supply adequate plasticity. This plasticity could not be met in the initial stage from the notch root with hydrogen charging. The relation between maximum remote stress and critical crack length among different notch lengths was shown to be a geometry-independent parameter of pure nickel, which can predict tensile strength under various notch configurations.

ジャーナルTheoretical and Applied Fracture Mechanics
出版ステータス出版済み - 6 2020

All Science Journal Classification (ASJC) codes

  • 材料科学(全般)
  • 凝縮系物理学
  • 機械工学
  • 応用数学


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